A marketing ploy by Waitrose on Twitter to find out why customers like shopping at the supermarket has spectacularly backfired with a flood of comments mocking its middle-class credentials.

The supermarkets asked followers of its Twitter feed to complete the sentence, ‘I shop at Waitrose because...’ but instead of receiving genuine replies they were barraged with thousands of joking put-downs.

One shopper said she went to the store because she ‘didn’t like being surrounded by poor people’